Homocarnosine is a normal human metabolite, the brain-specific dipeptide of gamma-aminobutyric acid (GABA) and histidine. (PMID 1266573). Increased concentration of CSF homocarnosine has been found in familial spastic paraplegia. (PMID 842287). Homocarnosinosis (an inherited disorder, OMIM 236130) is characterized by an elevated level of the dipeptide homocarnosine (Hca) in the Cerebrospinal fluid (CSF) and the brain and by carnosinuria and serum carnosinase deficiency, and can co-exist with paraplegia, retinitis pigmentosa, and a progressive mental deficiency. (PMID 3736769). In glial tumors of human brain the content of homocarnosine has been found to be lower than in brain tissue (PMID 1032224), while an increase in content of homocarnosine was observed in brain tissue of animals under experimental trauma of cranium. (PMID 1025883).

This compound belongs to the class of organic compounds known as hybrid peptides. These are compounds containing at least two different types of amino acids (alpha, beta, gamma, delta) linked to each other through a peptide bond.